Fabric draw-down mechanism for flat knitting machines

ABSTRACT

IN A FLAT KNITTING MACHINE FOR THE PRODUCTION OF SHAPED KNITTED GOODS HAVING THREE-DIMENSIONAL PORTIONS, AS FABRIC DRAWDOWN MECHANISM IS ARRANGED DIRECTLY BENEATH THE NEEDLE BEDS. THE MECHANISM INCLUDES A DRAW-DOWN ROLER COMPOSED OF PERIPHERALLY TOOTHED ROLLER COMPONENTS OF RELATIVELY SMALL AXIAL DIMENSIONS MOUNTED ON A FIRST ROTATABLE SHAFT AND SPACED APART BY ANNULAR RECESSES THROUGH WHICH DRAW-DOWN HOOKS CAN PASS, THE ROLLER THROUGH BEING DRIVEN BY THE FIRST SHAFT THROUGH AN ADJUSTABLE YIELDABLE DRIVE WHEREBY THEY CAN SLIP CIRCUMFERENTIALLY ABOUT THE FIRST SHAFT WHEN A PREDETERMINED LOADING IS EXCEEDED. COOPERATING WITH THE DRAW-DOWN ROLLER IS A COMPOSITE COUNTER PRESSURE ROLER COMPOSED OF INDIVIDUAL ROLLERS OF REDUCED AXIAL DIMENSION, THESE ROLLERS ADJUSTABLY BEARING AGAINST DRIVING DISCS WHICH ARE SECURED ON A SECOND ROTARY SHAFT AND DISPOSED BETWEEN THE ROLLERS, WHEREBY THE ROLLERS ROTATE TOGETHER WITH THE SECOND SHAFT SO LONG AS THE RESISTANCE DOES NOT EXCEED A PREDETERMINED MAXIMUM VALUE. THE DRAWN-DOWN HOOKS DURING THEIR PASSAGE THROUGH THE ANNULAR RECESSES BETWEEN THE ROLLER COMPONENTS ARE DEFLECTED TO BEAR AGAINST THE COUNTER PRESSURE ROLLERS SO AS TO PREVENT THE NEW KNITTING LOOPED IN THE HOOKS FROM BEING DISENGAGED THEREFROM BY THE ROTATING ROLLER COMPONENTS.

K. ESSIG Nov. 9, 1971 4 Sheets-Sheet 1 Filed Dec. 5, 1969 FIG] K. ESSlG 3,618,343

FABRIC DRAW-DOWN MECHANISM FOR FLAT KNITTING MACHINES Nov. 9', 1971 4 Sheets-Sheet 7:

Filed Dec. 5, 1969 Nov. 9, 1971 K. ESSIG 3,618,343

FABRIC DRAW-DOWN MECHANISM FOR FLAT KNITTING MACHINES Filed Dec. 5, 1969 4 Sheets-Sheet 5 F/Gz3 1 rrrrr FlG.4a 2/ Nov. 9., 1971 K. ESSIG 3,618,343

FABRIC DRAW-DOWN MECHANISM FOR FLAT KNITTING MACHINES Filed Dec. 5, 1969 4 Sheets-Sheet 4.

FIG.5

United States Patent FABRIC DRAW-DOWN MECHANISM FOR FLAT KNITTING MACHINES Karl Essig, Reutlingen, Germany, assignor to H. Stoll &

Company, Reutlingen, Germany Filed Dec. 5, 1969, Ser. No. 882,686

Claims priority, application Germany, Dec. 6, 1968, P 18 13 052.4 Int. Cl. D04b 15/88 U.S. Cl. 66149 16 Claims ABSTRACT OF THE DISCLOSURE In a flat knitting machine for the production of shaped knitted goods having three-dimensional portions, a fabric drawdown mechanism is arranged directly beneath the needle beds. The mechanism includes a draw-down roller composed of peripherally toothed roller components of relatively small axial dimensions mounted on a first rotatable shaft and spaced apart by annular recesses through which draw-down hooks can pass, the roller components being driven by the first shaft through an adjustable yieldable drive whereby they can slip circumferentially about the first shaft when a predetermined loading is exceeded. Cooperating with the draw-down roller is a composite counter pressure roller composed of individual rollers of reduced axial dimension, these rollers adjustably bearing against driving discs which are secured on a second rotary shaft and disposed between the rollers, whereby the rollers rotate together with the sec ond shaft so long as the resistance does not exceed a predetermined maximum value. The draw-down hooks during their passage through the annular recesses between the roller components are deflected to bear against the counter pressure rollers so as to prevent the new knitting looped in the hooks from being disengaged therefrom by the rotating roller components.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to fabric draw-down mechanisms for fiat knitting machines.

For the manufacture on flat knitting machines of shaped knitted goods provided with three-dimensional portions, such as brassiere cups and the like, a fabric draw-down mechanism is required which will be operative only at such times as, and such places where, new stitches are formed, but which otherwise will simply retain the fabric under a predetermined tension insufficient to draw it down. Since such three-dimensionally shaped portions are, however, only required at precisely pre-determined locations in the knitting, and the formation of new stitches takes place quite generally only at parts of the web of fabric which are continuously varying, it is important that the drawing down of the fabric shall not be effective simultaneously over the full width of the fabric but only at individual and comparatively narrow areas. In addition, the newly-formed stitches must be engaged and pulled down immediately following their formation.

It has already been proposed in French patent specification 1,390,039 to use draw-down rollers of smaller diameter than usual and to arrange these as an auxiliary roller system immediately beneath a needle bed. The problem stated above cannot, however, be solved by such means, because comparatively long draw-down rollers are used which apply a continuous pull over the entire width of the knitted web.

Fabric draw-down mechanism for use in the circumstances set out above must also be such that it can accommodate draw-down hooks which permit either the production of fresh beginnings to the fabric, or the production of widenings in the fabric and hence the insertion of a new starting piece or of appropriate widenings between the draw-down means.

The fabric draw-down mechanism according to the present invention achieves these objects. The said mechanism is arranged directly beneath the needle beds and is characterized in that it includes a draw-down roller composed of peripherally toothed roller components of relatively small axial dimension mounted on a first rotatable shaft and spaced apart by annular recesses through which draw-down hooks can pass, said roller components being driven by the first shaft under the influence of an adjustable pressure axially exerted upon them but being adapted to slip circumferentially about the first shaft when a predetermined loading is exceeded, and in that there is provided, for cooperation with said draw-down roller, a composite counter pressure roller composed of individual rollers of reduced axial dimension which rollers, by virtue of adjustable pressure against driving discs which are disposed between them and secured on a second rotary shaft on which the rollers are mounted, rotate together with said second shaft so long as the resistance thereby set up does not exceed a predetermined maximum value. The peripherally toothed roller components may be individually and independently mounted on the first shaft, or they may be connected in small groups to form subsidiary rolls, the subsidiary rolls then being driven under the influence of adjustable pressure axially exerted upon them.

Th efirst and second shafts on which the peripherally toothed drawn-down roller components and the counter pressure rollers are respectively mounted are drivingly connected with the drive means of the machine and driven through a coupling which is operated by the patterning device. This coupling is rendered effective only during working strokes of the cam carriage of the machine.

The thickness of each of the draw-down roller components is no more than the distance between two knitting needles.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more clearly understood and readily carried into practical elfect, a specific embodiment of the invention will be described, by way of example, with reference to the accompanying drawings, wherein,

FIG. 1 is a vertical cross-section through the frame of a V-bed flat knitting machine illustrating the application of the improved auxiliary draw-down mechanism with the draw-down hooks in their raised position.

FIG. 2 is a view similar to FIG. 1 but with the drawdown hooks retracted and deflected into their rest positions,

FIG. 3 is a section through part of the draw-down roller on an enlarged scale,

FIG. 4 is a similar section through the composite counter pressure roller,

FIG. 4a is a detailed cross-sectional view, drawn to an even larger scale, of a part of the counter pressure roller, and

FIG. 5 is a plan view of part of the frame of the aforesaid V-bed fiat knitting machine with the needle beds removed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, it will be seen that the two opposed neede beds 1, 2 are secured in known fashion to the frame 3 of a V-bed flat knitting machine. Attached to each of two bearers 4, 5 of angle form are mountmounting 7 has been fully shown in the drawings. The angled bearer 4 is rigidly screwed to the frame 3, whereas the bearer 5 is adjustable in guide slots 8, 9. Freely rotatable in the mounting 6 is a shaft and in the mounting 7 a shaft 11.

Disposed in axial alignment on shaft 10 (FIG. 3) are peripherally toothed roller components 12 which constitute the draw-down roller. Between the components 12 are annular recesses 13 each of which is sufliciently wide to admit of the passage, between any two adjoining ones of the said roller components, of a draw-down hook 36 hereinafter to be described. Each of the components 12 is of an axial dimension, i.e. thickness, which advantageously corresponds to the distance between two knitting needles. If desired, and as shown, the draw-down roller may be composed of a plurality of subsidiary rolls, such as 14, each comprising a small number, e.g. three or four, of the roller components 12 integrally formed together, the appropriate number of annular recesses 13 being formed in each such subsidiary roll. The subsidiary rolls 14 are disposed closely side-by-side and are pressed together against a collar (not shown) provided at the right-hand end of the rod 10 by means of a threaded nut 15 through the medium of a thrust ring 16 and a pair of spring washers 17. By virtue of the friction between the subsidiary rolls 14 the latter are all turned together with the shaft 10, although capable of being held relative to the shaft. Also secured to the shaft 10 is a pinion 18 which is arranged in mesh with a pinion 19 fastened to the shaft 11. Finally, a chain sprocket 20, also secured to the shaft 10, is driven by a chain from the drive of the machine through a clutch. The said clutch, which is not shown in the drawing, is operable from the patterning device of the machine. For co-operation with the draw-down roller, there is provided a composite counter roller comprising a plurality of co-axial pressure rollers 21 each of a width, i.e. length, corresponding either to that of the subsidiary rolls 14 of the composite draw-down roller, or to the combined thicknesses of say, three or four individual roller components 12, plus the combined widths of the annular recesses 13 therebetween in the case of a draw-down roller which is not divided up into subsidiary rolls but instead is formed of individual roller components. Each of these individual pressure rollers 21, which are of a resilient material, is a force fit on a sleeve 22. As shown in FIG. 4a, each such sleeve is provided at one end with a flange 23 and at the other end with a collar 24 having therein a recess 25. The pressure rollers 21 are lined up on the shaft 11 with driving discs 26 interposed between them. Each driving disc 26 is accommodated in the recess 25 formed in the relevant sleeve 22 and has a driving nose 26 for engagement in a groove 11 extending longitudinally through the shaft 11. The individual pressure rollers 21 require to be assembled in such a way that each of them lies exactly opposite to the corresponding subsidiary roll 14 or group of individual roller components 12, as the case may be.

The force with which the pressure rollers 21 are applied against the driving discs 26, and thus the frictional effect applied to drive the rollers 21, is adjustable by means of a nut 27 which acts on the thrust rollers 21 or the sleeves 22 through the medium of a thrust ring 28 and a pair of spring washers 29. By virtue of the fact that the pressure rollers 21 are pressed not only against one another but also against the driving discs 26 turning with the shaft 11, the frictional effect of the individual pressure rollers 21, and hence the draw-off tension to be exerted by the composite counter roller is much greater than that exerted by the draw-down roller. In the illustrated example, the pressure rollers 21 are also used for driving the subsidiary draw-down rolls 14. The draw-off pull exerted on a knitted web by the draw-down rolls 14 in co-operation with the counter pressure rollers 21 is, however, only suflicieut to hold the said web firmly under a predetermined tension. If this tension in the knitted 'web is relievedby the formation of new stitches, then the draw-down rolls 14 and the counter pressure rollers 21 turn together with their shafts 10 and 11 until the requisite tension in the web has been restored. Thereafter, the subsidiary draw-down rolls 14 and the counter pressure rollers 21 slip on the shafts 10 and 11. Accordingly, since the pressure rollers are rotatable substantially independently of each other, as are the roller components, each co-operating pair of a pressure roller and subsidiary roll can draw-down fabric independently of other such pairs, and the knitted fabric is drawn down only at such times as and locations where new stitches are formed. This occurs not only in aregularly knitted web, where stitch is made on stitch, but more especially in knitted fabrics of the hereinbefore mentioned kind having three-dimensionally shaped parts which are fabricated at specified locations only of the knitted fabric.

The individual pressure rollers 21, i.e. the composite counter pressure roller considered as a whole, is pressed against the draw-down roller constituted by the peripherally toothed components 12 by an appropriate lever system 30, 31 and 32. As shown in FIG. 5, this lever system acts on the bearer 5 through an inclined pressure bar 33.

The draw-down hooks 36 are secured in a bar 37 in known fashion and are adapted to be raised and lowered by an operating cam not shown in the drawings. Moreover, these draw-down hooks are mounted in a guide bed 38 capable of being turned about a pivot pin 39. The guide bed 38 is pulled by a tension spring 40 against a support roller 41, the latter being mounted on the upper end of a bar 42 which is adapted to be raised and lowered by cam oepration. A counter holder 43 attached to the frame 3 prevents any inadvertent deflection of the roller 41. The movements of the drawn-down hooks 36 and of the roller 41, effected by their respective cams, takes place in opposite directions. Thus, whenever the draw-down hooks 36 are raised the roller 41 is simultaneously shifted downwards, and vice versa. At the commencement of knitting a fresh web of fabric, or prior to widening knitted fabric, the drawn-down hooks 36 are pushed up into the annular recesses between the toothed roller components 12, as a result of which the hooks engage a thread, in the known way, and pull it between the knitting needles to form a course of loops. At this time the support roller 41 is located at a point approximately beneath the center of the counter holder 43. During further retraction of the drawndown hooks 36 and their passage between the peripherally toothed roller components 12 it is necessary for these hooks to be deflected somewhat to the left (FIG. 1) and to bear against the pressure rollers 21, thereby preventing the newly commenced knitting looped in the said hooks from being disengaged from the latter by the rotating drawdown components 12. This is achieved by providing the counter holder 43 with a concavity 44 which the roller 41 can enter. Whenever the bar 37 is retracted by a link 37 (the function of which can alternatively be performed by a weight), the bar 42 and the support roller 41 are simultaneously raised, the said roller entering the concavity 44 at an appropriate time. As a consequence, the guide bed 38 fulcrums about the pivot pin 39 as it is pulled leftwards by the tension spring 40 to effect the required deflection of the draw-down hooks 36. A further raising of the bar 42, following final insertion of the knitted fabric into the nip of the draw-down and counter pressure rollers, brings the support roller 41 and with it also the guide bed 38, finally into a position in which the draw-down hooks are disengaged from the fabric. That is to say, by a rearward swinging movement of the guide bed 38, against the action of the spring 40, the draw-down hooks 36 are deflected to positions behind and clear of the fabric so that the latter can pass the hooks without obstruction, all as shown in FIG. 3.

When the draw-down hooks 36 are lifted again, however, these are not required to be applied against the counter pressure rollers 21. Thus the concavity 44 in the counter holder 43 must be made ineffective at this time. For this purpose, a slide 46, arranged in a slideway 45 in the counter holder 43, is moved by the bar 42, through the agency of a driving pin 47 provided thereon, suchwise as to colse off the concavity 44 and so prevent the support roller 41 entering it. The slide 46 is returned by a second driving pin 48 appropriately positioned on the bar 42.

In addition to being applicable to a V-bed fiat knitting machine such as that illustrated, the hereinbefore described fabric drawn-down mechanism may, with appropriate constructional modifications not affecting the principle of operation thereof, also be applied to other types of flat knitting machines.

What I claim is:

1. In a flat knitting machine havnig needle beds, a fabric draw-down mechanism arranged directly beneath the needle beds, said mechanism comprising: a draw-down roller composed of a plurality of roller components mounted on and yieldably driven by a first rotatable shaft so as to rotate with the shaft to draw down fabric but to slip circumferentially about the shaft when a predetermined draw-down loading is exceeded, said roller components each being of relatively small axial dimensions and spaced apart by annular recesses through which drawdown hooks can pass; and a composite counter-pressure roller for cooperating with said draw-down roller, said counter-pressure roller being composed of individual pressure rollers of reduced axial dimension mounted on a second rotary shaft such that each pressure roller bears against a small predetermined number of said roller components so as to be rotatable together, and means forming an adjustable yieldable drive betwen said pressure rollers and said second shaft so that said pressure rollers rotate with said second shaft so long as the load on said pressure roller does not exceed a predetermined value, whereby knitted fabric between aid draw-down roller and said counter-pressure roller will be drawn down only at such times as and locations where new stitches are formed.

2. Apparatus as claimed in claim 1 wherein said roller components are peripherally toothed.

3. Apparatus as claimed in claim 2 wherein said drawdown roller includes means, rotating with said first shaft, for urging said roller components axially together with an adjustable pressure.

4. Apparatus as claimed in claim 2 wherein said means forming an adjustable yieldable drive between said pressure rollers and said second shaft comprises drive discs mounted on said second shaft for rotation therewith, and means for adjustably urging said pressure rollers against said drive discs.

5. A fabric draw-down mechanism according to claim 2, wherein said first and second shafts on which the peripherally toothed roller components and the counter pressure rollers are respectively mounted are drivingly connected with drive means of the machine and driven through the medium of a coupling which is operated by the patterning device of the machine.

6. A fabric draw-down mechanism according to claim 5, wherein the coupling is rendered effective only during working strokes of the cam carriage of the machine.

7. A fabric draw-down mechanism according to claim 2, wherein adjustable pressure is exerted axially upon the peripherally toothed roller components to press them frictionally together by an adjustable threaded nut through the medium of spring washers mounted on the first rotatable shaft.

8. A fabric draw-down mechanism according to claim 1, wherein said last mentioned means includes drive discs mounted on said second shaft between the pressure rollers, and adjustable threaded nut, and a spring washer; and wherein the individual counter pressure rollers are 6 pressed both together and also against the driving discs by the adjustable threaded nut through the medium of a spring washer mounted on the second rotatable shaft.

9. A fabric draw-down mechanism according to claim 2, wherein each of the peripherally toothed roller components is of a thickness not exceeding the distance between any two knitting needles in the machine.

10. A fabric draw-down mechanism according to claim 2, wherein the draw-down roller is of a composite form composed of a plurality of co-axial subsidiary rolls each comprising a small number of suitably spaced and integral peripherally toothed roller components, and said means forming an adjustable yieldable drive forms such a drive between the subsidiary rolls and the second shaft.

11. Apparatus as claimed in claim 1, wherein one of said shafts is relatively adjustable toward and away from the other shaft.

12. Apparatus as claimed in claim 1, wherein said pressure rollers are each of an axial dimension not exceeding the axial dimension of four roller components and the corresponding annual recesses.

13. Apparatus as claimed in claim 1, wherein the ma chine includes draw-down hooks for passing upwardly and downwardly through said annular recesses, further comprising means for deflecting the draw-down hooks toward and against the pressure rollers as the hooks pass downwardly through the annular recesses, so as to prevent the new knitting looped in said hooks from being disengaged therefrom by the rotating roller components.

14. In a flat knitting machine having needle beds for the production of shaped knitted goods having threedimensional portions, a fabric draw-down mechanism arranged directly beneath the needle beds, said mechanism comprising a draw-down roller and a counter-pressure roller, each of said rollers comprising a plurality of roller members of relatively small axial dimensions disposed axially on a shaft, the roller members on one of said shafts including annular recesses for the passage of draw-down hooks upwardly between the two rollers, the two shafts being substantially parallel, and means for yieldably driving said roller members in a fabric drawdown direction such that the knitted fabric is drawn down only at such times as and locations where new stitches are formed, and is otherwise held under a predetermined tension.

15. Apparatus as claimed in claim 14 wherein the roller members on each shaft are yieldably driven by their respective shafts, and the roller members on either shaft can be rotated or held stationary relative to other rollers on the same shaft.

16. Apparatus as claimed in claim 14 wherein the roller members on said one shaft are in the form of roller components each having an axial dimension at its periphery approximately corresponding to the distance between two adjacent knitting needles, and spaced apart by said annular recesses for the passage of draw-down hooks, and the roller members on the other shaft are each of an axial dimension not greater than four of the first mentioned rollers together with the included annular recesses.

References Cited UNITED STATES PATENTS 3,375,683 4/1968 Joseph 66-149 FOREIGN PATENTS 394,831 7/1933 Great Britain 66-149 RONALD FELDBAUM, Primary Examiner US. Cl. X.R. 66--150 

